Numerical Investigation on Temperature and Flow Characteristics of a Tornado-Like Vortex by using Large-Eddy Simulation

Abstract

The present work is about numerical simulations of the tornado-like vortex flow generated by our group based on LES techniques which is executed on a three-dimensional computational grid and results have been compared with experimental ones. Different subgrid-scale stress model and finite volume method are adopted to solve the low Mach number compressible Navier-Stokes equations using the different computational domain and boundary conditions, which are mainly to assess the model feasibility. All the simulations were performed using ANSYS FLUENT14.5 in consistency with the real experimental model which avoided the performances of the different techniques and turbulence models introducing other variables. Numerical results suggest that the vacuum degree, temperature difference and the rotation strength decayed in the axial and radial direction regularly changed with inlet gauge pressure p0 from 100 to 400 kPa which are consistent with experimental results. The accurate numerical simulation of this specific flow, resulting in an improved prediction capability of the flow and thermal properties of tornado-like vortex, could allow a correct estimation of the vacuum and energy separating performance of this device in strong rotating jet operation. Furthermore, computational results illustrate that strong rotating jet turbulent flow under the conditions of the certain pressure, temperature, velocity profiles and distribution can formed tornados-like vortex evolution and maintaining mechanism due to a large gradient in radial temperature, pressure and velocity balanced by inertia force, centrifugal force and rotational kinetic energy dissipation.